Good!!!
I will keep this thread.
Well that is where I got the s 3.6mm number for trace width! On the 1oz that is typical of these little board fab companies its an 8mm trace width. 
just silly. This is probably why not a lot of high amp boards are made. I am going to work on a two board with pin header for an attiny. YAY!
An update to my latest rev: I got it in the mail, I am going to try and populate one, but I am nervous that there are VIAs that are too close to the GP, the good thing is that it will show itself right away, the bad thing is a hot/cold cycle I don’t know if these chips were designed to take…
Thanks theomajigga. What makes your PCB different from the FET [People are pushing 15-20 amps with these] & MTN Buck Drivers [can handle up to 5.5 amps]. Both 17mm layouts.
Those drivers are essentially direct drive, so not 6V. There aren’t step up FETs or many different controllers for that matter.
An idea I’ve been toying with is using my driver to boost to 6V and then putting a few 7185s together for a CC package. I need to research this a bit more, that would SURELY be a 2 piece board. The heat is going to be the killer at this point.
EDIT: I forgot to preface this by saying that this is exciting work so far. Thanks for showing it off!
Wait, you showed a tailcap draw of 4.2A earlier. I don’t think we’re looking at 97 efficiency here… more like 65% efficiency, right?
Here are my assumptions:
Output = 1.5A @ 6.4v = 9.6W
Input = 4.2A @ 3.5v = 14.7W~
Efficiency = 9.6W / 14.7W = 0.65 = 65%
I take it that this design is CV then?
IIRC that’s the direction Lamdba went with the boost driver for VaraPower lights. It was a fairly different situation, but my understanding was that the driver worked well and provided a lot of power. If you are interested I think that the best information on that driver is available over here, starting with post #20.
It helps me! Thanks for posting the link, but don’t forget to include the post # since BLF’s forum software doesn’t behave nicely with direct links depending on your “view” settings. FWIW that’s Post #1616 over there.
is this the driver that fits the TF F13 ?
or is that the same concept but different diameter ?
This is excellent! Just what I have been looking for.
Excellent work!
Very interesting.
Such a driver would be most handy. MT-G2 is such a nice LED, but needing 2 x Li-ion to run it makes it less useful for anything EDC sized.
Hmmm MIA for over 2 weeks? Maybe he got erased for such a highly advanced driver, mysteriously vanished? Now you see him….now you don’t ?
Well, hop'n he's bizy working on those heat issues. From the OP, he's got a ways to go, but definitely on the right track. Hoping this works out.
I have to admit after seeing claimed 97% efficiency every other posts just looked like a blur. I’ll have to play skeptics too, that’s just way beyond what I can believe.
But if the OP is reading and really working on this, don’t let our skepticism get to you, keep up the good work.
I had offered to send him some LED parts for testing, but never heard back after initial contact. Hmm.
KD one is interesting, but it's big, specs are vague, and thinking there's some gotcha's with battery and LED configurations. It may be 3V-9V input and require at least 2 cells in series in order to support the 6V LED's, for example. I doubt it's doing boost and buck in that size and price.
- It’s huge compared to the driver theomajigga is shooting for. 22mm isn’t in the same ballpark as 17mm.
- As Tom E pointed out - it’s certainly just a buck driver. I’d be willing to wager quite a bit of money that the driver was based on either QX5241 or QX9920. Drivers of that size and type are common.
These are not the droids you’re looking for.
The new and very small Zebralight SC600 MkIII is running a single cell XHP35 - one owner measured about 4A at the tail. I assume their XHP35 is a 6V LED.
I wonder what size board they use? It has to be tiny and short (no stacked boards).
We already have single cell boost drivers in the Fenix PD40 (MTG2), Shadow JM35 (MTG2 and XHP50), Acebeam H10 (MTG2), Zebralight SC600 MkIII (XHP35) and SC63 (XHP35), so why hasn’t anyone cloned any of them yet?
Furthermore, Zebralights are known for maximum efficiency, not just small size.
XHP35's are 12V - listed here: http://www.mtnelectronics.com/index.php?route=product/product&path=60_114&product_id=569
Clone a boost driver? Uhhh - several have tried, several have died. Ok, not died, but gave up - same thing 
. Easy to say, not so easy to do, plus the costs could be insane for small qty runs. There's read locks on MCU's, part #'s filed off, mystery unknown parts with no identifying #'s, extremely small parts, multi-layer PCB's (layers you cannot see but are internal).
Quicker/cheaper to design from scratch, by the right engineer of course. But it's not quick or cheap.
In addition to what Tom E mentioned it’s hard to clone a driver we haven’t seen. Certainly we’ve seen the driver of the DQG tiny 26650 [comfychair] (don’t really like this setup currently) and the driver of the JM35 [M4D M4X] (new to me - probably similar to the DQG). I can’t easily find images of the PD40 driver or the others. I certainly haven’t seen detailed pictures of those drivers.
Often pictures aren’t enough. Take a look at that first thread I linked to - it took us a long time to figure out the basics of that driver, even with a willing comfychair prodding and taking voltage / resistance measurements and posting lots of large, clear pictures. If everyone involved had had one in hand the reverse engineering could have gone much faster. Tom E pointed out that it can be easier to design a fresh boost driver from scratch. This is accurate, but as Tom E mentioned one must understand the concepts involved in order to do it. While a circuit like the DQG 26650 for example can be reverse engineered without an understanding of those principles/concepts… it takes a large amount of work to determine values and part numbers for all the components. Sometimes it parts just can’t be identified without both measurements and a large knowledge of the industry… which most folks don’t get without already understanding the those principles/concepts mentioned earlier… bringing us back around to doing a fresh design rather than copying others.
I have an interest, but like others I have limited time. I don’t have the expertise to just lay out a problem free high-current boost driver in a day or two. RMM put in some work on a fresh boost driver over the summer but was unhappy with the results. Besides RMM, myself, and theomajigga I’m actually not aware of anyone else on BLF who’s (a) demonstrated that they have the knowledge to implement a boost driver like the one in this thread and (b) expressed an interest in doing so.